Electric switch



July 31, 1934- w.` H. PUTNAM l-:T AL 1,968,568

ELECTRIC SWITCH Filed Feb. 8. 1932 Patented July 31, 1934 1,968,568 ELECTRIC swrrcn William H. Putnam and Hamilton Putnam,

Ridgefield, N. J.; Carrie B. Putnam executrix of said William H. Putnam, deceased Application February 8 2 Claims.

This invention relates to an electric switch particularly adapted to be used in an alarm device for doors, the object of the invention being to cause a bell in an electric circuit to ring whenever the latch or bolt of a door lock is moved.

The device embodies an automatic switch which is placed in a box behind the striking plate of a door latch or bolt, so that when the knob or the lock is turned a Contact is established whereby a bell or buzzer indicates that somebody is at the door. It is impossible with the device of this invention to disengage a bolt or latch without the device giving warning. The

warning comes before the latch or bolt is disengaged from the striking plate and continues until closed, whereupon the closing of the door breaks the electric circuit which may be supplied by the door bell hookup. Y

Another object of the invention is to provide a device of the character set forth which can be inserted either behind the striking plate itself and clamped in position by the striking plate, or by making the box a part of the striking plate. If the device is separate from the striking plate, then friction holds the box in place and the bolt or latch is permitted to operate the switch by passing through the plate and contacting with an insulated portion of a rocker arm.

The device of this invention constitutes a unit as a whole, all the working parts being placed in a casing and held behind the striking plate frictionally by means of flanges on the casing. I desired, screws may be inserted through the flanges and into the door casing in order to securely hold the casing in position, but by clamping the device in the door casing by `means of the striker plate the installation is rendered easier and simpler, the only work of installation being embodied in fitting the device into a recess or mortise made in the casing and connecting the wires to the bell, or if desired, to a separate circuit. If desired, the device may be connected to a siren such as is placed outside of'A stores and business houses in general, which is something very efcacious after dark.

It will therefore be understood that the main object of this invention is to provide a simple device, easily installed, which will give warning of the slightest tampering with the door knob or attempts to open the door before the latch or bolt can be withdrawn from the striking plate and to continue the alarm after the door is opened. Upon closing the door the latch breaks 55 the connection. The device is also so constructed 1932, Serial No. 591,528

that it is adaptable to a door which opens inwardly or outwardly, the latch engaging the rocker arm to give the alarm in either case. The device of this invention is also provided with means to throw it out of operation when desired.v

Another object attained by this invention is that all the electrical connections are completely insulated and arev installed in such a manner that it will be very difficult for a burglar to cut them, as they are all hidden or enclosed.

The invention consists in an electric switch, of the character set forth in the following specication and particularly pointed out in the claims.

Throughout the specification and claims the word latch, is used, but the same may be construed as a bolt.

Referring to the drawing:

.Fig. 1 is a sectional elevation taken on line 1 1 of Fig. 2 and illustrating the switch posi'- tioned in a door frame, also showing in connection therewith the latch of a door and a portion of the door in .which said latch is positioned, the rocker arm of the device being shown in full lines in its normal position, that is, in the position assumed byit when the latch is protruding. into the casing of the device, while the rocker arm is shown in dotted lines in the position assumed by it when the latch isrwithdrawn.

Fig. 2 is a front elevation of the switch. Fig. 3 is a` rear elevation of the switch showing an electric circuit and bell connected therewith.

Fig. 4 is asectional plan'taken on Figli. l

' Fig. `5"is a ,perspective view of the brush whichk is incorporated in the velectric circuit to engage one of the contact members, and k Y I Fig. 6 is a sectional elevation similar to Fig. 1y illustrating a modified form of our invention.

Like numerals refer to like parts in the several views of the drawing.

In the drawing, referring to Figs. 1 to .5 inclusive, 10 is the door frame. 11 is a door. 12 is the striker plate fastened by screws to the door frame in the usual mannerand having an open-V ing 12' extending therethrough, the screws not being shown in the drawing. 13 is the latch of the door lock. 14 is a casing of the alarm device which is open at the front at 15 and at4 the rear ,at 16.` On opposite sides of the opening 15 there are provided flanges 17 which eX- tend throughout the entire height of the casing 14 and project outwardly therefrom to be engaged by the striker plate 12 and thus to clamp line, 'l-4,

ico

the casing, with the parts mounted thereon, to the door frame 10, or it may be screwed to the casing.

A block of insulating material 18 is fastened by a screw 19 to the bottom 20 of the casing 14 and this block of insulating material has embedded therein a metal plate 21 which is turned upwardly at 22 at the rear of the casing and fastened to the block 18 by a screw 23 to which one'end of the electric circuit 24 is attached. A screw 25 extends downwardly through the block 18 and engages the other end 26 of the metal connection plate 21, the screw 25 constituting one'of the contact members of the device. If desired, a wire conductor may be substituted for the plate 21.

A horizontal pin 27 extends across the casing and is fastened to the Walls 28 and 29 of said casing, forming a pivot for a rocker arm 30 which is mounted to rock on said pin and is rocked by a torsional spring 31, one end 32 of Which projects into the casing and the other end 33 of which projects into the rocker arm. The rocker arm has its lower end 34 arcuate in form, the arcuate portion being concentric with the pivotal pin27, and fastened to the lower end of the rocker arm is a metal plate 35, one end 36 of which projects into the front face of the rocker arm and the other end 37 projects into the rear face of said rocker arm, whereby the plate 35, which constitutes a contact member, is securely fastened to the rocker arm, which is made of insulating material.

The plate is connected at all times to the electric circuit by a brush 38 constituting a contact member and consisting of a device of spring metal having an upward and curvilinear arm 39 and right angle base 40 which is fastened by a screw 41 to the insulating block 18, the screw 41 also serving to connect to the insulating block and to the brush 38 one end of the electric circuit 24. A bell 42 and a battery 43 are illustrated in said electric circuit.

It will be noted that the median axial line of the pivotal pin 27 is located at one side of a median plane extending longitudinally of the rocker arm 30 and parallel to the axial line of the pin 27, so that normallyv the said rocker arm without the action of the spring 31 would tend to fall toward the right, Fig. 1, and contact at its upper right hand corner 44 with the latch 13, so that the device can be used without the torsional spring 31 but would not be so positive or quick inits action -as when the spring 31 is incorporated therein.

The rocker arm 30 may be locked in an inoperative position-byV means of aspring catch 45 which is fastened by rivets 46 to the top 47 of the casing 14. This metal catch terminates at its forward end in a hook 48 and normally when the rocker arm is in the position illustrated in full lines, Fig. 1, the hook 48 rides on a surface 49 forming the bottom of a recess 50 formed in the upper edge of the rocker arm. By moving the rocker arm rearwardly from the position shown in full lines, Fig. 1, until it is substantially in a vertical position, the hook 48 will drop into the downwardly extending portion 51 of the recess 50 and thus prevent the rocker arm from moving forwardly into the position shown in full lines, Fig. 1.

It will be noted that by having the spring catch 45 project into the recess 50, the upper end portions 52 and 53 of 30 may either of them be engaged by the latch of f a door, depending on whethinterior of the casing 14, the upper right hand corner 44 of the rocker arm will contact with the latch 13 of the door and will be held in the position illustrated in Fig. 1 with the contact member 35 out of engagement with the contact member 25 and thus the electric circuit being broken. 1f now the latch 13 of the door is withdrawn by turning the knob of the door or by a. key, then the rocker arm 30 will be moved forwardly from the position illustrated in full lines, Fig. 1, to the position illustrated in dotted lines therein and the contact member 35 will contact with the contact member25 and the electric circuit will be closed, thus ringing the bell 42. 'I'he bell will then ring until the door is closed, or until the latch is allowed to enter the casing 14 and push the rocker arm 30 from the dotted position to the full position, Fig. 1. If it is desired to lock the rocker arm out of operative position, it may be done by inserting the finger through the opening in the striker plate and pushingv the rocker arm back until the hooked end 48 of the catch 45 drops into the portion 51 of the recess 50. In order to prevent the rocker arm from being pushed backwardly so far that it will bend or injure the brush 38, the upper right hand corner 44 of the rocker arm will engage the top 47 of the casing before the end ofthe brush passes beyond the arcuate portion of the contact member 35. 1f the device is thrown out of operation by locking the rocker arm in a substantially vertical position by means of the hooked catch 45, it may be released and allowed to pass into its operative position by lifting the hooked end 48 out of the portion 51 of the recess 50 and then the parts will assume the relative positions illustrated in full lines in Fig. 1 when the door is closed and the latch is projecting into the casing.

In Fig. 6 we have illustrated a modified form of our invention which is like the embodiment of our invention illustrated in Figs. 1 to 5 inclusive, except that instead of the hooked catch 45 we employ a small bell-crank lever 54 which, when the rocker arm 55 is in the position illustrated in Fig. 6, projects into a notch 56 in the front face of the rocker arm 55. The arm 57 of the bell-crank lever 54 projects slightly beyond the front face of the casing and through an opening 58 in the striker plate 59. With this exception the embodiment of our invention illustrated in Fig. 6 is the same as that illustrated in Figs. 1 to 5 inclusive and operates in the same manner.

We claim:

1. An electric switch having, in combination, a casing, a pivot in said casing, a rocker arm of insulating material mounted on said pivot and projecting therefrom, an arcuate contactmember on said rocker arm, a projection provided on one end of said arcuate contact member, a pair of stationary contact members in electric circuit with each other on said casing, one of said stationary Contact members on the casing being at all times in contact with the arcuate contact member on said rocker arm, a spring on said casing connected to said rocker arm and adapted to move said rocker arm in one direction to cause the projection on said arcuate contact member to engage the other stationary contact member on the casing, whereby said electric circuit may be closed, and means to limit the movement of said rocker arm in the opposite direction.

2. An electric switch having, in combination, a casing with an opening therethrough, a pivot in said casing, a rocker arm mounted on said pivot and projecting therefrom, the lower end of said rocker arm being arcuate, an arcuate Contact 

